In general, the present invention relates to an information processing apparatus, an information processing method and a presentation medium. More particularly, the present invention relates to an information processing apparatus, an information processing method and a presentation medium which allow generation of a sound and a movement of a picture to be synchronized with each other in a 3-dimensional virtual reality space expressed in a VRML.
In the Internet serving as a computer network constructed at a world-wide scale, there is known a VRML (Virtual Reality Modeling Language) as a descriptive language capable of treating 3-dimensional information uniformly by making use of the construction of a WWW (World Wide Web) which provides various kinds of information.
As a system usable in the Internet for providing information, there is known the WWW which was developed by CERN (European Center for Nuclear Research) of Switzerland. The WWW allows information such as texts, pictures and sounds to be viewed or listened to in a hypertext format. To put it in detail, the information stored in a WWW server is transmitted to a terminal such as a personal computer asynchronously by using a protocol referred to as an HTTP (Hyper Text Transfer Protocol).
The WWW server comprises the HTTP, server software known as xe2x80x9cdaemonxe2x80x9d and an HTML file for storing hyper-text information. It should be noted that the daemon software is a program for executing control and processing in a background when doing jobs under UNIX. Hypertext information is expressed by using a descriptive language called an HTML (Hyper Text Markup Language). In a description of a hypertext written in the HTML, the logical structure of a statement is expressed in terms of format specifications which are each called a tag expressed by sandwiching a statement with the symbols xe2x80x9c less than xe2x80x9d and xe2x80x9c greater than xe2x80x9d. A link with other information is described by using link information referred to as an xe2x80x9canchorxe2x80x9d. When a location of information is specified by making use of an anchor, a string of characters known as a URL (Uniform Resource Locator) is utilized.
The HTTP is a protocol for transferring a file described in the HTML through the network. There are provided functions whereby a request for information is transmitted from a client to the WWW server and hypertext information of an HTML file is transferred to the client by the WWW server in response to the request.
Widely used as an environment utilizing the WWW is a WWW browser where the verb xe2x80x9cto browsexe2x80x9d of the word xe2x80x9cbrowserxe2x80x9d means xe2x80x9cto view here and therexe2x80x9d. To be more specific, the WWW browser is a client software represented mainly by Netscape Navigator, a trademark of a US company named Netscape Communication Corporation. By using the WWW browser, it is possible to browse the so-called home pages, that is, files represented by a URL on the WWW server of the Internet which is spread at a world-wide scale. To put it concretely, it is possible to make an access to a great variety of information sources on the WWW by tracing link-connected home pages from a page to a next one in an operation called net surfing.
In recent years, specifications of a 3-dimensional-graphic describing language referred to as a VRML have been developed to further expand the WWW. The 3-dimensional-graphic describing language allows a hypertext link to be set for a description of a 3-dimensional virtual reality space or an object rendered as a 3-dimensional graphic and allows accesses to be made sequentially to such descriptions and such objects through the WWW server by tracing their links. In addition, there has also been developed a VRML browser for displaying a 3-dimensional virtual space, which is described in accordance with the specifications of this VRML.
References describing details of the VRML include xe2x80x9cVRML: Browsing and Building Cyberspacexe2x80x9d authored by Mark Pesce, 1995 New Readers Publication ISBN 1-56205-498-8 and xe2x80x9cMost Recent Trend of VRML and CyberPassagexe2x80x9d authored by Kohichi Matsuda and Yasuaki Honda, compiling an articles in a Bit magazine of Vol. 28, No. 7 pp29 to pp36, No. 8 pp57 to pp65, No. 9 pp29 to pp36 and No. 10 pp49 to pp58 published by Kyoritsu in 1996. It should be noted that the former reference is translated by Kohichi Matsuda, Terutaka Uraji, Shohichi Takeuchi, Yasuaki Honda, Junichi Toshimoto, Masayuki Ishikawa, Ken Miyashita and Kazuhiro Hara into Japanese and published by Prentice Hall Publication ISBN4-931356-37-0 with a first edition published on Mar. 25, 1996.
In addition, a formal and complete specification sheet of xe2x80x9cThe Virtual Reality Modeling Language Version 2.0, ISO/IEC CD 14772xe2x80x9d, is disclosed at xe2x80x9cwww.vrml.org/Specifications/VRML2.0/FINAL/spec/in dex.htmlxe2x80x9d. A version written in Japanese is disclosed at xe2x80x9cwww.webcity.co.jp/info/andoh/VRML/vrm 12.0/spec-jp/index.htmlxe2x80x9d.
As a browser for VRML2.0 and software for a shared server, Sony Corporation which is the applicant of this patent has developed xe2x80x9cCommunity Place (Trademark) Browser/Bureauxe2x80x9d as a commercial product. xcex2-version (a prototype) of this product can be downloaded from a home page on the Internet at xe2x80x9cvs.sony.co.jpxe2x80x9d.
With such VRML2.0, it is possible to describe and express an independent behavior of an object in a 3-dimensional virtual reality space. In order to create VRML contents, in which an object actively moves around in the 3-dimensional virtual reality space using VRML2.0, it is necessary to proceed a series of work like the one described below. VRML contents are a collection of information such as VRML files and script files used for implementing a series of object""s behaviors in one virtual reality space.
The following is a description of a series of work to create VRML contents.
Work to create a model is a job to describe attributes of an object or a model such as the shape and the position thereof located in a virtual reality space in VRML2.0 and to make a basic VRML file.
Description of a sensor node is a work to add a description of the sensor node to a VRML file. An example of the sensor node is TouchSensor which is used for generating an event when a click operation or a pointing operation is carried out by means of a mouse. Another example of the sensor node is TimeSensor for generating an event at a point of time set in advance.
Work to edit a routing is a job to add a description of a routing to a VRML file. A routing is used for propagating an event generated by a pointing operation or the like carried out on a sensor node associated with an object.
Description of a script node is a work to add a description of the script node to a VRML file. A script node is used for passing an event propagated through a routing to an external script.
Creation of a script file is a work to describe or to program a script in a language such as the Java for expressing behaviors of objects in a virtual reality space set in advance on the basis of an event passed by way of a script node. It should be noted that Java is a trademark of Sun Microsystems Corporation, a US company.
Desired VRML contents are created by doing the various kinds of work described above.
In order to create VRML contents accompanying an independent behavior of an object in a virtual reality space, it is necessary to form the shape of the object and to create animation by using existing authoring software called a modeler and to output the work as a file of the VRML2.0 format. An example of the authoring software is 3D Studio Max, a trademark. If the modeler does not support the VRML2.0 format, it is then necessary to convert the format of the output file into the VRML2.0 format by using a tool such as a converter.
Subsequently, descriptions of a variety of sensor nodes as well as other descriptions expressed in VRML2.0 format are added to a VRML file by using a text editor, and pieces of work such as creation of a script in the Java by using the text editor, addition of a script node associated with the Java script and addition of a route statement are done repeatedly. Finally, in verification of an actual behavior of an object, a VRML browser for VRML2.0 is activated to check the behavior of the object by carrying out operations such as clicking by means of the mouse.
In addition, with VRML2.0, a user is allowed to increase the number of node types by defining a new node type. In addition, a node of the newly defined node type can be used as if the node were an existing built-in node. A new node type defined by the user is referred to as ProtoType. A keyword xe2x80x9cPROTOxe2x80x9d is used in defining ProtoType.
By the way, a processing time of picture data is not prescribed particularly in VRML2.0. For example, assume processing to display a movement of an avatar, a model or an object in a 3-dimensional virtual reality space, from a point P1 to another point P2 as shown in FIG. 1. In this case, there is no prescription which states that the processing has to be carried out in a predetermined period of time. For this reasons, the time necessary for moving the avatar from the point P1 to the point P2 varies in dependence on the performance of an information processing apparatus for executing a program for such movement.
In processing to generate a sound in a 3-dimensional virtual reality space, on the other hand, once generated, the generation of the sound has to be executed in a real-time manner. To put it concretely, take up reproduction of a piece of music as an example. In this case, the time for reproducing the piece of music from its beginning to the end thereof is fixed without regard to what information processing apparatus is used for the reproduction.
As a result, a problem is encountered in the design of a program for a 3-dimensional virtual reality space by means of a predetermined information processing apparatus wherein generation of the sound of a predetermined piece of music is started in synchronization with the start of the movement of the avatar from the point P1 and, then, precisely ended with timing synchronized with the arrival of the avatar at the point P2 as shown in FIG. 1. To be more specific, while the generation of the sound can be ended synchronously with the timing of the arrival of the avatar at the point P2 by executing the program on the predetermined information processing apparatus, the execution time of the program varies from apparatus to apparatus. This is because characteristics of the information processing apparatus such as the CPU""s clock frequency and the picture processing performance thereof vary from apparatus to apparatus.
As a result, there is a problem that a movement of a picture can not be synchronized with generation of a sound accompanying the movement by using the conventional VRML2.0 software as described above. For example, the avatar may not be reached to P2 although the generation of sounds has already terminated, or vice versa.
It is thus an object of the present invention addressing the problem described above to synchronize a movement of a picture with generation of a sound accompanying the movement.
An information processing apparatus for presenting a 3-dimensional virtual reality space expressed in a VRML according to claim 1 is characterized in that said information processing apparatus includes a specification means for specifying a sound source, an output means for outputting data of a sound source specified by said specification means as an event, a display control means for displaying a picture of a predetermined object, and a modification means for making a change to a picture of said object related to an event output by said output means.
An information processing method for presenting a 3-dimensional virtual reality space expressed in a VRML according to claim 2 is characterized in that said information processing method includes a specification step of specifying a sound source an output step of outputting data of a sound source specified at said specification step as an event a display control step of displaying a picture of a predetermined object; and a modification step of making a change to a picture of said object related to an event output at said output step.
A recording medium for recording a computer program to be executed by an information processing apparatus for presenting a 3-dimensional virtual reality space expressed in a VRML according to claim 3 is characterized in that said recording medium is used for providing a computer with an information processing method comprising a specification step of specifying a sound source an output step of outputting data of a sound source specified at said specification step as an event a display control step of displaying a picture of a predetermined object, and a modification step of making a change to a picture of said object related to an event output at said output step.
In the information processing apparatus according to claim 1, the information processing method according to claim 2 and the recording medium according to claim 3, when data of a sound source is output as an event, a change related to the output event is made to a picture of an object.